Colon cancer is the second most frequently diagnosed malignancy in the United States. Cancer of the gastrointestinal tract, especially colon cancer, is a highly treatable and often a curable disease when localized to the bowel. However, currently colon cancer is the second most common cause of cancer death. Surgery is the primary treatment and results in cure in approximately 50% of patients. Recurrence following surgery is a major problem and often is the ultimate cause of death. The prognosis of colon cancer is clearly related to the degree of penetration of the tumor through the bowel wall and the presence or absence of nodal involvement. These two characteristics form the basis for all staging systems developed for this disease. Bowel obstruction and bowel perforation are indicators of poor prognosis. Elevated pretreatment serum levels of carcinoembryonic antigen (CEA) and carbohydrate antigen 19-9 (CA 19-9) also have negative prognostic significance.
Because of the frequency of the disease (approximately 160,000 new cases of colon cancer per year), the identification of high-risk groups, the demonstrated slow growth of primary lesions, the better survival of early-stage lesions, and the relative simplicity and accuracy of screening tests, screening for colon cancer should be a part of routine care for all adults starting at age 50, especially those with first-degree relatives with colorectal cancer.
Procedures used for detecting, diagnosing, monitoring, staging, and prognosticating colon cancer are of critical importance to the outcome of the patient. For example, patients diagnosed with early colon cancer generally have a much greater five-year survival rate as compared to the survival rate for patients diagnosed with distant metastasized colon cancer. Treatment decisions are usually made in reference to the older Dukes or the Modified Astler-Coller (MAC) classification schema for staging. However, new diagnostic methods which are more sensitive and specific for detecting early colon cancer are clearly needed.
Further, colon cancer patients must be closely monitored following initial therapy and during adjuvant therapy to determine response to therapy and to detect persistent or recurrent disease of metastasis. Thus, there is clearly a need for a colon cancer marker which is more sensitive and specific in detecting colon cancer recurrence.
Another important step in managing colon cancer is to determine the stage of the patient's disease. Stage determination has potential prognostic value and provides criteria for designing optimal therapy. Currently, pathological staging of colon cancer is preferable over clinical staging as pathological staging provides a more accurate prognosis. However, clinical staging would be preferred were the method of clinical staging at least as accurate as pathological staging because it does not depend on an invasive procedure to obtain tissue for pathological evaluation. Staging of colon cancer would be improved by detecting new markers in cells, tissues, or bodily fluids which could differentiate between different stages of invasion.
In the present invention, methods are provided for detecting, diagnosing, monitoring, staging, and prognosticating colon cancers, particularly colon, stomach, and small intestine cancer, via nine (9) Colon Specific Genes (CSGs). The nine CSGs refer, among other things, to native proteins expressed by the genes comprising the polynucleotide sequences of any of SEQ ID NO:1, 2, 3, 4, 5, 6, 7, 8 or 9. In the alternative, what is meant by the nine CSGs as used herein, means the native mRNAs encoded by the genes comprising any of the polynucleotide sequences of SEQ ID NO:1, 2, 3, 4, 5, 6, 7, 8 or 9 or levels of the genes comprising any of the polynucleotide sequences of SEQ ID NO:1, 2, 3, 4, 5, 6, 7, 8 or 9.
Other objects, features, advantages and aspects of the present invention will become apparent to those of skill in the art from the following description. It should be understood, however, that the following description and the specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only. Various changes and modifications within the spirit and scope of the disclosed invention will become readily apparent to those skilled in the art from reading the following description and from reading the other parts of the present disclosure.